Releasing device for locking pliers



Feb. 16, 1954 D 2,669,145

RELEASING DEVICE FOR LOCKING PLIERS Filed Oct. 5, 1952 2 Sheets-Sheet l a 10 Ba 4 l7 5 Fig. 5

) p Q V INVENTOR jf m er H. M6607 HTTYS Feb. 16, 1954 H. A. MEAD RELEASING DEVICE FOR LOCKING PLIERS 2 Sheets-Sheet 2 Filed Oct. 5, 1952 INVENTOR fzfomer f], Mead BY {Ii/4.2 mull ATTORNEYS Patented Feb. 16, 1954 UNITED STATES PATENT OFJ-FI-"(ZEJ 2,669,145 antmsme harms ronnocnmc rmens mer-am n, Turlock, Calif'. Annlicationpctobenz, 1952, Serial No. 312,913

' ,14 Claims, (entail-s4) This invention relates to; self-docking wrenchl ers of thatitypeso -tcon.stnict d1thatv the ijaw connecting linkage moves past. dead, center, when the jaws tightly r p apiece-oiwork, d l ks said jaws against release.

The major object of ,this inyentiqnjsitoprovide a simple, and efficient device mounted on the plier nd. operable by a finger of the .vh nd, gra ping the pliers, for breaking the dead centerilock so that the jawsv and.,,the.ir., controllin -1 handles may be opened. or spread withoutwsubstantial resistance.

,Afurther object is. to, provide a device, for the purpose, arranged totexert a great, releasing forcejonthe parts to be releasedwitha mini mum of. finger: -.pressure;,- the. device working smoothly, positively, and quickly. I

Such device includes .a fingerlever, and anotherobject of the invention is to arrange. this lever so thatit is in a position most, convenient and natural for operation; by a finger of. the hand holding the pliers; thev lever. having, a minimum ofprojection when in its normal position.

A further object of the invention is to. provide a releasing device, for locking pliers, which, is designed for easeandeconomy of manufacture,

, A/ still further object ofvthe inventionis, to provide a practical andv reliable releasing devicefor locking pliers, and a device'which is exceedingly effective for the purpose for. which it isdesigned,

These objects are, accomplished by.means "of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

Fig; 1 is-aside elevationbf'the pliers'with the jaws spread to: straddlearpieceofjwork such as a nut before engaging the same.

7, Fig.2 is, asimilar view, partlyibrokenout and insection, showing the jaws of 'thepliersgripping the work locked against release.

i Fig. 3 isa similar view, but with thetlock released by actuation of the fin errlever.

-;Fig. 4 is a fragmentary .crosstSection onyline Ilal Of'FjiQzQ.

1' Fi 5 -,is ,a fragmentary transver section on line 55 of Fig. 1.

Referring now more particularly to the characters of reference on the drawings, the pliers comprises stationary and movable jaws I and 2, respectively; jaw i being rigid with a straight elongated handle 3, which is of dee U-shaped form in section, with the opening of the U facing away m the outer ge at the handle as plainly shown in Fig. 4,

Thejaw 2 is formed withzashaman -projec ng at an angletosaidjaw and between? the-3id=5 of handle 3, the shank being pivoted to:sa j V a relatively short distancebelow jaw-.l bwa, in 6.

A handle 1',-also,-of deep u-form in ross'section to provide spaced sides 8 and opening'in the-directionof handle3, is pivoted at its-forwa nd' by apin I 9 on shank 41 adjacent its: outer side at a point generallyopposite pivot 6.

The handles are connected by-a rigidtogglfi link l0 which includes a: fQIWQTd 'PQlFIiOIT-"Ql l, of rectangular cross section to fit-closely between the sides 8 and '5 of therhmdlesanda; rearward threaded portion l2, fitting-inclearancewrelaticn between the sidesiofhandle l The link e e s n v-o theazhandl siand is pivoted at its forward; end" onv the handles sides 8 by a. cross pin; 13; disposed some -;di,stance; rear wardly of pivote and'clear of jaw shank};

A knurled finger nut 14 rofgreatermd-iameter than the outside width of;- handle; 3--is threaded on link portion l2. The nut is @Onfinedain, the

sides 5; of handle-3 by and proj ectsthrough ea er formin op nings I Bout-throu h said walls; The bottom walls of: the openings arershaped; tor-form transversely alined fulcrum points engaging andv about which the nutmay rock 5 the; innerside and forward walls of theopenin sbeing curved;

as at H, about said fulcrummoints-as an axisyand confining the nutwithout; restricting its rotation; This enables the link; andnut-toswing; as a-unit about the fulcrums l6 without.materialdriction as handle 1- isswungflto open and close themovable jawZrelative to the-fixed jaw L. 'Theopene ings, however; are elongatedat' them-outer side as shown at I511 for: the: initialeinsertion 10f"; the nut I4,

The pivot --l3-is disposed-relative toxaline It raw hrough the fulcrum point-l 6 and the; axis of.;pivot9 so that pin:l3,is;disposed laterally in froinsaid; line-when the handles are brought to, gether with the jawsgtightlygrippedwithaepiece of work suchas anut N, as shown in Fig. 2;.

:The jaws are thus locked' against being opened by any pr ssureexerted' on the. jaws-at thework, and in order to break; the.;lock',:in arsimpleiand arrangement is tric to the axis of pivot It to provide a cam face 23 disposed so that the distance from the cam face to said pivot increases rearwardly. The link I is disposed so as to be engaged by the cam face 23 when the handles are closed. In order to enable the lever to be as long as possible and still project but little from the back of the handle, the portion I I of the link It) is formed as a dog leg bent away from the finger lever, the outer edge or face 24 of the portion II rearwardly of the bend being that engaged by and disposed at a considerable angle to said cam face. It may here be noted that the threaded portion I 2 is not affected by the shape of portion II, and said threaded portion remains radially disposed relative to pin I3.

The lever 20, in its inoperative position is disposed at the upper end of slot 2I, being yieldably held in that position by a leaf spring 25.pressed at its lower end into a notch 26 cut in the upper side of the lever 20 back from the pivot, and extending thence forwardly to slidably bear against back of the handle I inside the same and ahead of the slot.

The eccentric face 23 is so related to pivot 19 and to the link face 24 that as the cam is rotated, by pulling rearward on lever 20, said face rolls on or walks easily along face 24 without slipping (Jr-appreciable friction, and hence a greater and more positive cam pressure can be exerted on link I0. Also, Wear on the contacting faces is reduced to a minimum and practically eliminated.

With this arrangement, therefore, and with the link locked past dead center, it is only necessary to pull lever 20 rearward, as shown in Fig. 3. Because of the eccentric relation of cam face 273 to pivot I9 and face 24, this causes the handle I to be swung out relative to handle 3, the cam rolling on link face 24 without slipping, as described. This handle movement is, of course, accompanied by an outward movement of link pivot I3, the link swinging about the fulcrum points It.

Aiso, because of the above described eccentric cam face arrangement, a relatively slow but very great leverage is exerted at the outset of the lockbreaking operation, when it is most needed, while a lesser leverage and faster movement occurs toward completion of such operation, as is also desirable. Additionally, the relatively great length of lever 20, made possible by the dog-leg or recessed form of the upper portion of the link Ill, enables the desired action to be obtained with a minimum of finger pull.

It is to be further noted that lever normally extends at a forward diagonal from pivot I3 so that the tip 22 is initially ahead of said pivot l9, while the eccentric cam face 23 is rearwardly of such pivot. This arrangement of parts is advantageous, as the finger imparted motion of tip 22, required to release the pliers, is rearward as distinguished from laterally inward whereby the releasing force does not oppose or Work against the opening movement of the handle 1.

From the foregoing description, it will be readi- 1y seen that there has been produced such a device as substantially fulfills the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent is desired:

1. In wrench type pliers including relatively movable handles and a beyond dead center looking unit connected diagonally between said handles, the movable handle being channel shaped and opening inwardly; a releasing unit comprising a lever extending laterally of the pliers and disposed mainly in the channel of the movable handle with'its inner end adjacent the locking.v unit, said movable handle having a longitudinal slot through which the outer end of the lever projects, a cross pin pivoting the lever adjacent its inner end on said handle, and a cam on the inner end of the lever engaging the locking unit and arranged to impart a releasing movement to said locking unit upon actuation of the lever and movement of the outer end thereof in a direction away from the jaws.

2. A pliers as in claim 1, in which the cam is disposed close to the pivot pin and is arranged relative thereto to exert the greatest leverage against the locking unit at the inception of the actuating movement of the lever and to roll upon the unit with movement of the lever about the pivot pin; the leverwhen in its initial position being disposed at an acute angle to the locking unit in the direction of the jaws so that the outer end of the lever is then closer to the jaw end of the pliers than the pivot of the lever.

3. A pliers as in claim 1, in which the cam is disposed close to the pivot pin and is arranged relative thereto to exert the greatest leverage against the looking unit at the inception of the actuating movement of the lever and to roll upon the unit with movement of the lever about the pivot pin; said point of greatest leverage of the cam being substantially on a line drawn through the pivot pin and the outer end of the lever.

4. A pliers as in claim 1 in which the locking unit includes a link against which the cam bears; said link being deflected inwardly intermediate its ends and away from a straight line drawn through said deflected portion of the link.

HOMER A. MEAD.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 2,489,895 Kash NOV. 29, 1949 2,514,130 Jones July 4, 1950 2,519,973 Mead Aug. 22, 1950 2,523,385 Mead Sept. 26, 1950 2,532,659 Burns Dec. 5, 1950 2,576,286 Eisenberg Nov. 27, 1951 2,598,650 Smith et a1 May 27, 1952 2,604,803 McC'ann July 29, 1952 

